Process of coloring clay



Patented Jan. 12, 1932 UNITED PATENT;-oFFicE BER'r r. VANDERIBILT, or nnw yonx," N. un, nssren'on ro R. vnnnnnmn'r- COMPANY, me, on NEW: YORK, n; Y., A oonronarron on NEW YORK v? I rnocnssgoncononrne.oLAY i N Drawing.

This invention relates to an improyed I f process of colorlng clay, and more particu-f larly to a process of coloring clay 1n a cont1nu-' ous manner while the'clay is in a dryand 'finely divided state and othe w in 'o tion for marketing. V

Secondary clays, of the kaolin type, suchas is "form of veins underground, fron which the overburden is removed to uncover the vein of clay. The clay vein may be, for example,

around 16 feet thick and usuallyconta ins the elay in a Wet state, requiring-drylng and clay is not ordinarily of uniform character,

but contains admixed impurities such as-par ticles of quartz, flakes of mica, etc and may 'bOntain clay particles of difierent sizes.

One common method of preparing the clay I for market has been to admix it With af large amount of water to make it into a thin slurry color all particles of the clay." After settling;

the dyed clay mud requires dryingto remove the large amount of Water which'it retainsfl l The process ofthepresent invention is one whi ch is carried out in connection withthe drying and dry grinding of clay in a continuous manner, and in which the dyeing'or'colop ing of the clay is carried ,out after the drying" and grinding operation and while the'elay is. in its state of ultimate subdivision or fineness preparatory to marketing.

In one of theimportant embodiineiitsiof o g I I V ing, preferably in rotary :driers',;andas af" I the invention, the clay is subjected tofdrying and dry grinding ina continuous mari grinding, andoften requiring'coloring or: dyeing, before the clay" 1s marketed; Thener and the dried and finely divided clay is then subjected to the coloring treatment as a part of its continuous methodi'of handling, and while the finely divided clayiis stillihotfl from the :drying operation; 1althoughr in its' broader aspects the process is not hrr'iited"to .Application filed attii 154 9 e1iiatfloi 1445,2337,

1S0 also, in one ofthe importante nbodi-" ments of the inventiomthe driedand pulver-ffrj,

fize diclay, is subjected to an air separation or? airflotation treatmenttoremove""theifine particles of clay fromthe coarser particles j ofclay and grit, ete.,;andthe finely divided 7 .air floated, clay is then'collected while' stilli o those which occur in the States of Northand; South Carolina and Georgia, occur in the hot and subjected to the coloringtreatment 1n a continuous manner; althoughin itsj broader. aspect-ls the process is notlimited' 'to 'w the coloring of air separated clay. 1 I The improved coloring treatment of the" present invention is carried out upon afiow e I ingstreamof the finely divided clay, which 7 may or maynot have beensubjected to anfi f" air separat on. treatment, and which is ad-Q vantageously still hot from the drying oper f Mien, yapp 'y b e clay, efer b yi thelform-of a spray or mist, a solutionfofja dye, so that the dye solutionpenetratespart "701 ofl'the clayand isabsorbedifthereby and f colorspart'of the clay particles,'and theclay isflthen further treated-asa part ofthe tontinuous iprocss tofe ffect uniform distribu j 5 tionjofthe colored clay particles among those which have not been colored so as to produce p i a composite colored clayproduct. containing] dyed particles distributed with'substantially v uniform distribution throughout 'the entire i v s i t Thetreatmentiofthe wetclayoto' convert body of Clay. 1 itinto a form suitablefor marketing requires" I, that the clay h'au be. dried and crushed. Thewet mined claylmaybe directlyerushedfin arock'crusher such as between rolls spacedf? say.l/ }inch' apart, or the clayocan-be' first air]? v driedbefore"the-"first rough 'crushing'lf'Iir I the w'inter'time," when the. water fibnta'ined infthelelayfis frozen, a hammer millftypeof" preliniinary' crusher can be employed The"9 v:

rough crushed clay is'then subjected wary-*5 continuous operation} The clay entering the drier is" more or less small lump'orpellet -form,' and the dried clay j mayllstill .beto" 'a' The dried clay "is then subjeetedtd further o i grindingi orcrushing to break upgthe lumps o and: separate the clay; int'o 'fin'e' particles. 7 I

* 1,841,309; I q I V the end of the crushing operation.

selective type of air separator. 7 Such a selec tive separation can be carried out in; the Gayco dry centrifugal separator or in the Sturtevant selective type of separator." In such .separator, the air is repeatedly recirculated and brought into contact with the hot finely dividedclay and removes the finer particles of the 'clay by aseiective air separation treatment. The clay thus separated from the main body of clay in the separator ,is c ollected from the air and the remaining 5 body "of'clay can then be subjected to further separation in another air separator. practice, a series of two or three o-rrmo're of these -separators can be employed in series, with progressive removal of the fine clay particles leavin thecoarser cla 7 articlesand particles of grit, etc, behind to be discharged as a'coa rser clay product.

' The finely divided clay which is separated by the selective air separation is collected "whileit'is'stillhot and is conveyed by a suitableconveyor, such as'a screw conveyor, to a place i'of "storagefor packaging or shipment.

Injcarrying out the present process I subject 'the 'fin'ely"divided clay, after the air "separation treatment, and before storing or paliaging" o1- shipment, to-the dyeing or col-f oring treatment by applying the ,dye ad-v mixed with water to a flowing stream of the: finely divided clay, the dye preferably being applied in the form of. a fine spray or mist, for example, spraying a regulated amount of the dye solution continuously onto a moving body of the fine clay. The spraying of ,the hotclay with the dye solution results in the distribution of the mist or spray over the movingclay sothat the dye-solution is. absorbe'd by the clay particleswhich come in contactwith the particles of spray or mist,

This results in the dyeing of some of the clay vparticles and theabsorption of the water of the" dye the clay particles, but with agitae tion of the clay, the dyed particles aregad-- mixed with the undyed particles and dis tributedin a uniform manner throughout the clay'mass. The heat of the clay will serve to remove any execess ofwater applied with j the dye, although, if the amount of dye solution: is sufficiently small, the water may be so distributedthroughout the clay mass as'to be un'objectionable even where the clay has been cooled before the dye is applied and where the water of. the dye solution remainsstma greater orless extent in the'dyed clay. Theadmixingofthe dyed particles offine clay with the undyed particles can be carried out as a part of thecontinuous movement of the clay, for example, in a worm conveyor, as it leaves the air separating ma chine and passes to the storage bins or pack- I ages. A worm conveyor is an efiicient mix- I 'ing device for mixing the dyed fine clay particles with the undyed particles'to give a composite product in which the dyed particles are distributedthroughout the mass, to give to the clay a uniform colored appearance.

The nature and amount of the dye employe'dcan be varied, depending upon the purpose for which the clay is to be used, but for dyeing light colored clay to give it'a bluish, color so that it may be used in paper making, a blue dye, such as dry acid blue B can be employed, using, for example, 0.0 pounds of dye per ton of finely divided clay and using the dye in solution in plain water so that about 2.5 gallons of the solution are added for each ton of finely divided clay. The application of such a dye solution to the finely divided clay will result in an intense coloration ofsomeof the clay particles, but with uniform distributionofthe dyed clay particles throughout the undyed clay particles, the efi'e ctis to give a more or less uniform dyed appearance to the clay, for example, a bluish appearance such as is desirable for-clay for paper making purposes.

} lVhile the dyeing of clay is desirable for certain purposes, it may not be desirable for other purposes. For example, thebluing of clay is important where the clayis to be employed for paper making, but is objectionable V wherertheclay ist-o be used for certain kinds ofpaint or other purposes. If the entire amount of clay ,is colored or dyed before it is crushed and before it is separated into different portions,ithe clay cannot thereafter be separated into. a;dye'dportion and an undyed portion; but-by applyingthe dyeing treatment, to the finely divided air floated clay,

; afterithasbeen separated from the remainderof the clay, itis possible-to obtain'a gritfree dyed claywhich is desired in the paper industry, while leaving behind in the air separator an undyed'clay whichis adapted. for use,'for example, forfthe paint industry where coloring is not desired. Itis impor tant, in the paper industry, to obtain clay which-is free from grit, and the present procl ess of dyeingthe finely divided airfioated clay gives directly a gritgfree dyed clay, leaving the remainder of the 'clay,whichmay contain admixed grit, and which may be valuable for painta'n'd other pur1 3oses,vin an undyed state. W

rheaf eiri eat finely divided clay is,

more ov er,:conibined with the handling of the clay, as apart. of a. :continuous process, so

that the ;.clay requires a 7 minimum of additional handlingg For example, where the clay is subjected to rough crushing, to drying tion of the heat contained in the still hot clay particles for removing any excess of water added with the dye, enables the clay to be conveyed continuously from the air separator to the storage or packaging or shipping containers, reaching them not only in a dyed statebut also with the dye uniformly distributed throughout the clay.

While I have referred to the use of a worm conveyor for conveying the clay from the air separator to the-storage or shipping or packaging department of the plant, the process'is not, limited to the use of such a worm conveyor, although that type of conveyoris advantageous as a conveyor and asa mixer.

. A suitable squirrel cage type of mixer could I ished, dyed clay product.

be employed for mixing the dyed clay particles with the undyed clay particles to give a uniformly appearing clay product, and this product could th'enbe conveyed to the place of storage, packaging or shipment, as a fin- It will thus be seenthat the present in vention provides an improved process of preparing clay in a continuous manner for the market,with dyeing of the finely dividedfinished clay in a continuous manner and as a part of the mill operation and handling of the clay. It will further be seen that the present process provides for the-direct production of finely divided air-floated and gritfree dyed clay while at the same time permitting the simultaneous production of undyed clay suitable for other purposes.

I claim 1. The improvement in the dyeing of clay which comprises drying and disintegrating the clay to convert theclay into the desired 7 fineness for marketing, and dyeing the fine dried clay by applying thereto, in a continuous manner, a solution of a dye to dye certain of the clay particles without dyeing others, and continuously mixing the dyed clay particles with the undyed clay particles to give 7 a clay product of uniformly dyed a pearance, the amount of water added witht e dye solution being so limited that subsequent treatment for the removal thereof isunnecessary, and so that the dyedclay can be di-' rectly conveyed to'storage, packaging or shipping containers. e e

2. The process according to 'claim' 1 in will assist in removingwater added dye solution. 7

3. The process accordin which the dried and crushe clay is subjected to air separation andthe finelydivided airin the separated clay is subjected to the continuous dyeing treatment to give directly a dyed gritfree clay, while leaving the portion of the' clay which has "not been separated by air floating in an undyed condition.

4. The method of treating clay which coinprises rough-crushing the clay, then drying it in a continuous manner by'lieating it to'a high temperature, then crushing the dried clay to convert it into a finely divided state, then subjecting the dried and finely divided clay, while still hot, to a selective air sepato claim 1 in ration treatment to remove fine particles of Y the clay in a substantially grit-free condition, collecting the finely divided .clay in a continuous manner and while still hot from the drying operationand applyingthereto in a continuous manner a dye solution to dye some of the clay particles without dyeing others, and intimately mixlng the resulting clay in a continuous manner toefiect uni form distribution of the dyed clay particles throughout the undyed clay'particles. r In testimony whereof I afiix my signature.

ROBERT. T. VANDER BILT...

- which the dye solution is applied to the fine,

ly divided clay While it is still hot from the drying operation so that the heat of the clay 

